As 2010 draws to a close, it is evident that despite great strides toward the Healthy People 2010 objective to eliminate racial disparities in health, we have fallen short of achieving our goal for coronary heart disease (CHD). In part, progress has been hampered by the need to rely on the Atherosclerosis Risk in Communities (ARIC) study for incidence rates, a study which recruited participants >20 years ago. These data may not be helpful in answering why Black-White disparities for coronary heart disease (CHD) mortality may be widening. Furthermore, Blacks enrolled in ARIC were recruited primarily from a single community in a high CHD mortality region. Similar to the more widely recognized Stroke Belt, US county level CHD mortality varies as much as 10 fold; the ARIC study cannot examine regional differences. As a result, we still do not know why Blacks have lower myocardial infarction (MI) incidence yet higher CHD mortality than Whites. The REasons for Geographic And Racial Differences in Stroke Study is generating data needed to study racial and regional differences in acute CHD. This prospective cohort, recruited from 2003-7, includes 30,239 community dwellers age >45 years at baseline residing in the 48 contiguous US states, with 42% Blacks (n=12,490) and 55% women (n=16,612). Rich baseline data include medical history, functional status, health behaviors, psychosocial measures, physiologic measures (BP, height and weight), blood and urine biomarkers (e.g., cholesterol, albuminuria, CRP) and ECGs. Our preliminary data from REGARDS-MI-1 reveal smaller Black-White CHD incidence differences for participants age <65 years compared with those age >65 years. Furthermore, in follow-up conducted to date, nonfatal acute MI incidence rates are highest in high CHD mortality regions for Whites, but not for Blacks. Together, these findings suggest that racial differences in incidence in the ARIC study may not be generalizable. The number of CHD events currently available (352 definite/probable MI, 187 CHD deaths) is insufficient to examine the reasons underlying these provocative early findings. We now seek funding to extend follow-up, aiming to: 1. To estimate region and race-specific rates of definite or probable MI, acute CHD mortality, including in- and out-of-hospital deaths, and sudden death. H1. Acute nonfatal MI incidence for Blacks and Whites is similar for those age <65 years, but lower for Blacks versus Whites age >65 years. H2. Acute nonfatal MI incidence varies by region and is highest in high CHD mortality regions for Whites, but not Blacks. H3. Acute CHD mortality is higher for Blacks than Whites overall, and across all CHD mortality regions. 2. To identify potential explanatory factors for racial difference in nonfatal and fatal CHD. H1. Traditional Framingham Heart Study (FHS) CHD risk factors, non-FHS CHD risk factors, CHD preventive practices (AHA's Life's Simple 7) and CHD preventive services differ between Whites and Blacks, in part explaining higher CHD mortality in Blacks. Exploratory H2. Susceptibility to some CHD risk factors differs for Blacks and Whites in part explaining higher White CHD incidence and higher Black CHD mortality.